Study of Flavour Changing Neutral Currents in Top Quark Decays with the CMS Detector

Abstract

This paper contains the first realistic estimate for the CMS sensitivity to Flavour Changing Neutral Currents (FCNC) in the top quark sector. The non-Standard Model decays t->Zq and t->γq (where represents or quarks) have been studied at 14 TeV exploiting the leptonic decays of the Z boson and the photon. A realistic detector simulation has been adopted and the most important systematic effects have been addressed. The 5- sigma discovery limits for the two decays are BR(t->Zq)=11.4x10^-4 and BR(t->γq)=5.7x10^-4, allowing some models of new physics to be tested.